Ferrule polishing fixture

ABSTRACT

The present disclosure relates to a device for holding a plurality of fiber optic connectors. The device includes a clamp defining a plurality of ferrule receiving openings, a set plate with openings for the fibers, an alignment surface on which the ferrules rest, and an actuator for moving moveable portions of the clamp. The clamp has a plurality of moveable portions that at least partially define the ferrule receiving openings. The moveable portions are moveable between a rest, biased closed position in which the ferrules are clamped within the ferrule receiving openings, and an open position in which ferrules can be inserted in the ferrule receiving openings.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.10/061,732, filed Feb. 1, 2002; which application is incorporated hereinby reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to the field of polishingfixtures for holding fiber optic cables during the polishing process.

BACKGROUND OF THE INVENTION

[0003] Fiber optic connectors generally include a cylindrical ferrulecontaining an optical fiber. A tip of the fiber is exposed at an endface of the ferrule. To enhance signal quality, it is desirable topolish the end face of ferrule. During the polishing process, theferrule is commonly held in a fixture, and the end face is pressedagainst a rotating polishing wheel or disk. An example of a fixture foruse in polishing fiber optic connectors is described in co-pending U.S.patent application Ser. No. 09/400,334, filed Sep. 21, 1999, whichapplication is incorporated herein by reference.

SUMMARY OF THE INVENTION

[0004] One aspect of the present invention relates to a device forholding fiber optic connectors having ferrules containing opticalfibers, the device including a clamp having a nest sized to hold aferrule. The nest includes a moveable portion moveable between a firstposition where the nest is sized to receive the ferrule and a secondposition where the nest is sized to clamp the ferrule. The moveableportion is biased toward the second, clamped position.

[0005] A variety of advantages of the invention will be set forth inpart in the description that follows, and in part will be apparent fromthe description, or may be learned by practicing the invention. It is tobe understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrates several aspects ofthe invention and together with the description, serve to explain theprinciples of the invention. A brief description of the drawings is asfollows:

[0007]FIG. 1 is a top plan view of an embodiment of a fixtureconstructed in accordance with the principles of the present invention,the fixture is shown with nests of the fixture in the biased closedorientation;

[0008]FIG. 2A is a top plan view of the fixture of FIG. 1 in place on anactuating device with the nests in the biased closed orientation;

[0009]FIG. 2B is a top plan view of the fixture of FIG. 1 in place on anactuating device, with the nests in an open orientation;

[0010]FIG. 3 is a cross-sectional view taken along section line 3-3 ofFIG. 1;

[0011]FIG. 4 is a top plan view of an embodiment of an actuating deviceconstructed in accordance with the principles of the present invention;

[0012]FIG. 5 is a top plan view of an alternative set plate;

[0013]FIG. 6 is a cross-sectional view taken along section line 6-6 ofFIG. 5; and

[0014]FIG. 7 is a top plan view of an alternative embodiment of anactuating device.

DETAILED DESCRIPTION

[0015] Reference will now be made in detail to exemplary aspects of thepresent invention that are illustrated in the accompanying drawings.Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or like parts.

[0016] The present invention relates to a system for holding fiber opticconnectors to facilitate polishing ferrules of the connectors. Onerepresentative embodiment of the invention includes a fixture 30 havinga plurality of clamps for holding ferrules. The clamps are normallyclosed. The system also includes an actuation device 123 for opening theclamps to allow the ferrules to be inserted into or removed from theclamps.

[0017] In use of the system, the fixture 30 is mounted on the actuationdevice 123, and the actuation device 123 is used to simultaneously openthe clamps. The ferrules of the connectors desired to be polished arethen inserted into the clamps. After insertion of the ferrules, theactuation device 123 releases the clamps thereby allowing the clamps toreturn to their normally closed orientation. In the normally closedorientation, the clamps securely hold the ferrules within the fixture.Thereafter, the fixture can be removed from the actuating device andmounted on a polishing device (e.g., a polishing wheel including apolishing film mounted on a polishing pad, as is conventionally known inthe art). After the ferrules have been polished, the fixture 30 isreturned to the actuation device 123, and the clamps are opened to allowremoval of the polished ferrules.

[0018] I. Fixture

[0019]FIGS. 1, 2A and 2B show an embodiment of a fixture 30 constructedin accordance with the principles of the present invention. The fixture30 includes a holding plate 32 defining a central opening 40 and havinga plurality of nests 34. An advantage of the fixture 30 is that it is anintegral structure, cut from a single piece of material, and does notinvolve removable parts. Each nest 34 defines an opening 36 sized forreceiving a ferrule of a fiber optic connector. The openings 36 extendcompletely through the plate 32 between upper and lower surfaces/sides142 and 144 (shown in FIG. 3) of the holding plate 32. The nests 34 arecircumferentially spaced about a reference axis 38 positioned at thecenter of the holding plate 32 (i.e., the nests 34 are arranged in acircular array).

[0020] Each nest 34 includes a moveable portion 42 moveable between afirst, open position where the nest is sized to receive the ferrule(shown in FIG. 2B) and a second, closed position where the nest is sizedto clamp the ferrule (shown in FIG. 2A). The moveable portion 42 isbiased towards the second, closed position. The moveable portion 42 canbe in the form of a flexible, cantilevered portion moveable between arest position in which the nest is clamped, and a flexed position inwhich the nest is open.

[0021] The nests 34 are opened by applying a displacement force on themoveable portion 42 in the direction indicated by the arrows in FIG. 1.The displacement force can be provided by any actuating device. Oneembodiment of an actuator is described in detail below. In oneembodiment, the moveable portions 42 have free end portions 54 thatextend into the central opening 40 for receiving the displacement force.While FIGS. 1, 2A and 2B show twelve nests 34 in a fixture 30, thefixture 30 can contain a single nest 34 or any number of nests 34.

[0022] In the embodiment shown in FIGS. 1, 2A and 2B, the holding plate32 includes a plurality of fixed portions 44 and a plurality of moveableportions 42 forming a plurality of nests 34. The fixed portions 44oppose the moveable portions 42. In one embodiment, free end portions 54of the moveable portions 42 extend beyond the fixed portions 44. Firsthalf-portions 60 of the nests 34 are formed by the fixed portions 44 andsecond half-portions 62 of the nests 34 are formed by the moveableportions 42 of the holding plate 32. Moveable portions 42 are formed byfirst and second slots 46, 48 cut from the central opening 40 andextending radially outwardly. The first slot 46 extends through theopening 36 of the nest 34. The second slot 48 is offset from the firstslot 46 to form the cantilevered moveable portion 42. The cantileveredmoveable portion 42 joins the fixed portion 44 at a flexing point 45.The moveable portions 42 are moveable relative to the fixed portions 44.For example, each of the moveable portions 42 is moveable between an atrest position (shown in FIG. 2A) and a circumferentially displaced, orflexed, position (shown in FIG. 2B).

[0023] When the nests 34 are in the at rest, or clamped position, thefirst and second half-portions (60, 62) of the nest 34 are sufficientlyclose together to clamp a ferrule. When a displacement force moves themoveable portion 42 away from the fixed portion 44, the second slot 48narrows and the first slot 46 widens, thus opening the nest 34.

[0024] The moveable portions 42 are biased toward the at rest positionsof FIG. 2A by inherent spring-like characteristics (i.e., elasticity orresiliency) of the material forming the moveable portions 42. In oneembodiment, the fixture 30 including the moveable portions 42 are madeof stainless steel. Preferably, the moveable portions 42 are displacedcircumferentially in a flexing motion. When the displacement force isremoved, internal spring-like characteristics bias the moveable portions42 toward the at rest positions.

[0025] By way of non-limiting example, the holding plate 32 can be madeof heat treated steel. Also by way of non-limiting example, the plate 32can have a thickness of about 0.21 inches, a height of about 4.725inches and a width of 4.725 inches; the first and second slots 46, 48can have thicknesses of about 0.0025 inches and 0.014 inches,respectively; and the nest openings 36 can have an open positiondiameter of about 0.099 inches.

[0026] To enhance gripping when the nests 34 are in the clampedpositions, the nests 34 can each include one or more bumps, projections,or irregularities (not shown) that extend radially into the openings 36.Also, to accommodate various connector configurations, depressions 50are provided about the nests 34 in the upper side 142 of the holdingplate 32. The depressions 50 are sized to receive portions of certainstyles of connector housings (e.g., SC type connectors).

[0027] II. Actuator

[0028]FIG. 4 shows one embodiment of an actuator device 123 constructedin accordance with the principles of the present invention. The actuatordevice 123 has an integral set plate 121. The set plate 121 includesseating surfaces 124, an inset ring 125 with at least one alignmentsurface 127, and a circular array of openings 126. The inset ring 125can be a separate piece, or it can be a region ofthe set plate 121. Theset plate 121 also includes a plurality of fixture pins 128 that alignwith corresponding alignment apertures 56 in the holding plate 32.

[0029]FIGS. 5 and 6 show an alternative embodiment of a set plate 121′with the alignment surface 127′ of the inset ring 125′ divided intoregions of differing elevations to provide a variety of offset distancesfrom the seating surfaces 124′ to accommodate various protrusionrequirements for different ferrule sizes. Regions 180 of the alignmentsurface 127′ without openings 126′ accommodate ferrules without fibers.

[0030] The openings 126, 126′ are positioned to align with the nests 34of the holding plate 32 when the fixture 30 is mounted over the setplate 121, 121′. The openings 126, 126′ are preferably smaller that theend faces of the ferrules desired to be polished, but larger than thefibers positioned within the ferrules. The openings 126 can all be thesame size as shown in FIG. 4, or a plurality of different size openings126′, 170 can be present on a single inset ring 125′, as shown in FIG.5. The larger openings can be used for larger ferrules to receive thelarger amount of epoxy residue that sometimes surrounds the fiber at theend faces of such ferrules. A set plate 121′ with an inset ring 125′containing both different elevation regions and different sizes ofopenings 126′, 170 reduces the number of set plates required to providedifferent ferrule offset lengths as may be required by differentpolishing processes. Typically, only surfaces of the same elevation areused to set the elevation of a given batch of ferrules.

[0031] The actuator device 123 includes a disk-shaped rotatable drive132 that projects upward through a central opening 134 defined by theset plate 121. The rotatable drive 132 includes a plurality of posts 52around the outer circumference. When a fixture 30 is placed on the setplate 121, as shown in FIG. 2A, the posts 52 are positioned between freeend portions 54 of moveable portions 42 of nests 34.

[0032] A lever arm 140 including an L-shaped handle 150 is mechanicallycoupled to the rotatable drive 132. By pivoting the lever arm 140outward and inward, the rotatable drive 132 with posts 52 is rotated inclockwise and counterclockwise directions, respectively. In oneembodiment, the posts 52 are rotated about 5-15 degrees in eachdirection.

[0033] As show in FIG. 4, the lever arm 140 is coupled to the rotatabledrive 132 by a linkage. The lever arm 140 is linked to the frame of theactuator device 123 at a first pivot point 154, and to an intermediatelink 152 at a second pivot point 156. The intermediate link 152 islinked to a drive link 160 at a third pivot point 158. The drive link160 is fixedly connected to the rotatable drive 132.

[0034] When the lever arm 140 is pivoted outward, as shown in dottedlines in FIG. 4, the rotation drive 132 and posts 52 are positioned awayfrom the moveable portions 42 of a fixture 30 present on the actuatordevice 123. Pivoting the lever arm 140 inwards, as shown in solid linesin FIG. 4, rotates the rotatable drive 132 counterclockwise, forcing theposts 52 against the moveable portions 42, which opens the nests 34.

[0035] III. Methods of Use

[0036] In use, the fixture 30 is positioned over the set plate 121 ofthe actuator device 123 with the lever arm 140 pivoted outward. Thefixture pins 128 of the set plate 121 are aligned with the alignmentapertures 56 of the fixture 30. The nests 34 are in the biased clampedposition as shown in FIG. 2A. The lever arm 140 is pivoted inwardcausing the rotatable drive 132 to rotate. As the rotatable drive 132rotates, torque from the rotatable drive 132 is transferred to themoveable portions 42 of the fixture 30 through the posts 52. The torquefrom the rotatable drive 132 causes the moveable portions 42 to move, orflex, from the biased closed position of FIG. 2A to the open position ofFIG. 2B. This movement of the moveable portions 42 causes the nests tomove to the open positions. The fixture pins 128 prevent the holdingplate 32 from rotating along with the moveable portion 42.

[0037] Ferrules of fiber optic connectors are individually inserteddownwardly from the upper side 142 of the holding plate 32 into theopenings 36 of the nests 34. The ferrules are pushed downwardly throughthe openings 36 until end faces of the ferrules protrude beyond thelower side 144 of the holding plate 32 and are seated upon the alignmentsurface 127 of the inset ring 125, and the optical fibers and epoxyresidue extend into openings 126 in the inset ring 125. This ensuresthat all of the ferrule end faces are aligned along a common plane.

[0038] With all the ferrule end faces seated on the alignment surface127 of the inset ring 125, the lever arm 140 is pivoted outward causingthe posts 52 to move away from the moveable portions 42. This allows themoveable portions 42 return to the rest, biased closed, position of FIG.2A such that the ferrules are firmly clamped within the nests 34 toinhibit relative movement thereinbetween.

[0039] With the ferrules clamped in the fixture 30, the fixture 30 isremoved from the set plate 121 and transferred to a polishing wheel (notshown) where the end faces of the ferrules are polished. The one-piecefixture 30 provides the advantage of having the nests 34 in the clampedposition without requiring any external force or added lockingmechanisms. With no additional moving parts or locking mechanisms, theone-piece fixture is easy to manipulate and clean.

[0040] After polishing, the fixture 30 is once again placed on the setplate 121, the lever arm 140 is pivoted inward causing the posts 52 tomove the moveable portions 42 to the open, flexed position of FIG. 2B,opening the nests 34 so the polished ferrules can be removed from thefixture 30. Thereafter, the process can be repeated on a subsequentbatch of fiber optic connectors.

[0041] IV. Alternative Actuator

[0042]FIG. 7 shows an alternative embodiment of actuator device 223.This embodiment includes features for insuring uniform protrusion offerrules from a polishing fixture. The actuator device 223 includes aset plate 221, swing clamps 310, a rotatable drive 232 and a lever arm240. The set plate 221 has seating surfaces 224 and an alignment surface227. A plurality of spring plungers 320 are embedded in the seatingsurfaces 224. The set plate also includes a plurality of fixture pins228 that match alignment apertures 56 in a fixture 30 to preventrotation of the fixture 30 during the clamping and setting process.

[0043] The spring plungers 320 are moveable between a first, at rest,position in which they extend above the seating surfaces 224, and asecond, retracted, position in which they are substantially flush withthe seating surfaces 224. Swing clamps 310 extend above the seatingsurfaces 224 and include clamp arms 315. The clamp arms 315 arerotatable toward the set plate 221 to clamp a fixture 30 placed onto theset plate 221. The clamp arms 315 are also moveable in a downwarddirection, toward the seating surfaces 224. The clamp arms 315 may beactivated in any mainer, such as pneumatically.

[0044] The alignment surface 227 has a plurality of openings 226positioned to align with nests 34 of a holding plate 32 when the fixture30 is mounted over the set plate 221. The actuator device 223 includes adisk-shaped rotatable drive 232 that projects upward through a centralopening 234 defined by the set plate 221. The rotatable drive 232includes a plurality of posts 252 around the outer circumference.

[0045] A lever arm 240 including an L-shaped handle 250 is mechanicallycoupled to the rotatable drive 232. By pivoting the lever arm 240outward and inward, the rotatable drive 232 with posts 252 is rotated inclockwise and counterclockwise directions, respectively. The lever arm240 is coupled to the rotatable drive 232 by a linkage. The lever arm240 is linked to the frame of the actuator device 223 at a first pivotpoint 254, and to an intermediate link 252 at a second pivot point 256.The intermediate link 252 is linked to a drive link 260 at a third pivotpoint 258. The drive link 260 is fixedly connected to the rotatabledrive 232.

[0046] In use, an empty fixture 30 is positioned on set plate 221 withfixture pins 228 aligned with the alignment apertures 56 of the fixture30. The fixture 30 rests on spring plungers 320 above seating surfaces224. The lever arm 240 is pivoted to rotate the rotatable drive 232 andposts 252, causing the nests 34 to move to the open positions. Ferrulesof fiber optic connectors are individually inserted into the openings 36of the nests 34. The ferrules are pushed downwardly through the openings36 until end faces of the ferrules are seated upon the alignment surface227 and the optical fibers extend into openings 226 in the set plate221. With all the ferrule end faces seated on the alignment surface 227,the lever arm 240 is pivoted outward, causing the nests 34 to close.

[0047] Once the ferrules are clamped in the nests 34, the swing clampsare activated. The clamp arms 315 rotate over and above the fixture 30,and then descend toward the seating surfaces 224. As the clamp arms 315exert a downward force, the spring plungers 320 retract and the fixture30 is made to contact the seating surfaces 224. The combined force ofthe swing clamps 310 must be sufficient to overcome the combinedresistance of the spring plungers 320 and the clamped ferrules. Thefixture is pre-staged by inserting and clamping the ferrules while thefixture 30 is above the seating surface 224 on the spring plungers 320.This assures that once the fixture is drawn snugly against the seatingsurface 224, any ferrules not fully inserted will still end up withidentical protrusion dimensions as those fully inserted.

[0048] The fixture 30 is then removed from the set plate 221 andtransferred to a polishing wheel (not shown) where the end faces of theferrules are polished. After polishing, the fixture 30 is once againplaced on the set plate 221, the lever arm 240 is pivoted inward,opening the nests 34 so the polished ferrules can be removed from thefixture 30. Thereafter, the process can be repeated on a subsequentbatch of fiber optic connectors.

[0049] Having described preferred aspects and embodiments of the presentinvention, modifications and equivalents of the disclosed concepts mayreadily occur to one skilled in the art. For example, while the nestsillustrated herein are configured to hold ferrules in a verticallyupright orientation, it will be appreciated that the nests could also beoriented so as to each hold a ferrule at an oblique angle relative to apolishing surface. However, it is intended that such modifications andequivalents be included within the scope of the claims that are appendedhereto.

What is claimed is:
 1. A device for holding a fiber optic connectorhaving a ferrule containing an optical fiber, the device comprising: aclamp including a nest defining an opening sized to hold a ferrule, thenest including a moveable portion moveable between a first positionwhere the nest is sized to receive the ferrule and a second positionwhere the nest is sized to clamp the ferrule, the moveable portion beingbiased toward the second position.
 2. The device of claim 1, furthercomprising a plate, wherein the moveable portion of the clamp includes acantilever located between slots defined within the plate.
 3. The deviceof claim 2, wherein the plate includes a plurality of clamps eachincluding a nest, the nests having moveable portions biased towardsecond positions where the nests are sized to clamp ferrules, themoveable portions including cantilevers located between slots defined bythe plate.
 4. The device of claim 3, wherein the plate defines a centralopening, and the plurality of nests are positioned about a circumferenceof the central opening.
 5. The device of claim 4, wherein free endportions of the cantilevers project into the central opening.
 6. Thedevice of claim 4, wherein the slots include first slots that extendradially outwardly from the central opening and through the openings ofthe nests, and second slots that extend radially outwardly from thecentral opening and are offset from the first slots.
 7. The device ofclaim 1, wherein the clamp further includes a fixed portion that opposesthe moveable portion.
 8. The device of claim 1, wherein the moveableportion projects beyond the fixed portion and is adapted for receiving adisplacement force for moving the moveable portion between the first andsecond positions.
 9. A device for holding a fiber optic connector havinga ferrule containing an optical fiber, the device comprising: a clampincluding a nest sized to hold a ferrule, the nest including a flexiblecantilever portion moveable between a first, flexed, position where thenest is sized to receive the ferrule and a second, at rest positionwhere the nest is sized to clamp the ferrule.
 10. The device of claim 9,wherein the device includes a plurality of the clamps.
 11. The device ofclaim 10, wherein the nests of the clamps are arranged in a circulararray.
 12. A device for holding fiber optic connectors having ferrulescontaining optical fibers, the device comprising: a plate including aplurality of nests, each nest defining a nest opening for receiving oneof the ferrules, each nest including a cantilever positioned on one sideof the nest opening and a fixed portion positioned on an opposite sideof the nest opening; each cantilever being located between a first plateslot that extends though the corresponding nest opening and a secondplate slot offset from the first plate slot; and the cantilevers beingflexibly moveable between first, flexed, positions where the nests aresized to receive the ferrules and a second, at rest position where thenests are sized to clamp the ferrules.